Gauss (unit)

In physics, gauss (symbol G) is the unit of strength of magnetic flux density |B| (also known as magnetic induction). The gauss belongs to the Gaussian and emu (electromagnetic) systems of units, which are cgs (centimeter-gram-second) systems. The unit is related to the SI unit tesla (T) as follows

1 G ≡ 1 Mx/cm² = 10⁻⁴  T.

The unit is named in honor of the German mathematician and physicist Carl Friedrich Gauss.

Definition

The gauss is defined through an electromotive force $\scriptstyle {\mathcal {E}}$ induced by a change in magnetic field B. For constant surface S and uniform rate of decrease of |B|, Faraday's law takes the simple form

$|\mathbf {B} |={\frac {\Phi }{S}}=-{\frac {t\,{\mathcal {E}}}{S}}.$

Hence, gauss is maxwell per unit surface, where maxwell (symbol Mx) is the Gaussian unit for the magnetic flux Φ, and |B| is a flux density.

In Gaussian units S is in cm², time t in s, $\scriptstyle {\mathcal {E}}$ in abV ( = 10⁻⁸ volt), |B| in G, and Φ in Mx:

1 G = 1 Mx/cm² = 1 abV⋅s/cm²

Related units

• The tesla (T) is the corresponding SI unit for B. 1 T corresponds to 10 000 G.
• The oersted is the Gaussian unit of strength of a magnetic field H. Note that the oersted is defined by means of an electric current that gives H.